The preparation method of high-purity butyl lactate

Abstract

The invention relates to a preparation method of high purity butyl lactate. The method is characterized by: taking industrial lactic acid and n-butyl alcohol as raw materials, and adopting benzene as a water-carrying agent, subjecting them to an esterification reaction in the presence of a catalyst, then carrying out vacuum distillation and refining, thus obtaining the high purity butyl lactate. Specifically, the catalyst is a composite catalyst of potassium hydrogen sulfate and ferric trichloride, or a composite catalyst of p-toluenesulfonic acid and sodium hydrogen sulfate. The method provided in the invention shortens the esterification reaction time, increases the yield of butyl lactate, simplifies refining operation, and is easy to realize industrialization.

Description

technical field [0001] The invention relates to a preparation method of high-purity butyl lactate. It belongs to the field of petrochemical industry. Background technique [0002] The chemical name of butyl lactate is alpha-hydroxypropionate butyl ester, which is a butyl ester derivative of lactic acid produced by the fermentation of carbohydrates similar to sugar and butanol. It is a colorless transparent liquid with a sweet taste. Cream aroma and milk aroma, easily soluble in most organic solvents such as ethanol, ether, acetone, esters, etc., partially hydrolyzed when miscible with water, non-toxic, good solubility, and completely biodegradable in nature. [0003] Butyl lactate is widely used in chemical, pharmaceutical, food and other industries. Solvent-grade butyl lactate is a high-quality green and environmentally friendly high-boiling solvent used in natural resins, synthetic resins, spices, paints, printing inks, dry cleaning fluids, and adhesives. Special specif...

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Problems solved by technology

[0004] Chinese patent CN102030644 discloses a preparation method of butyl lactate. This patent uses lactic acid and n-butanol as raw materials, and uses sulfuric acid-loaded activated clay as a catalyst. The disadvantages are: sulfuric acid is too acidic, and the post-treatment is complicated, causing much pollution.

Chinese patent CN1450046 discloses a high-yield, high-optical-purity L-butyl lactate synthesis method. This patent uses lactic acid and n-butanol as raw materials, and uses concentrated sulfuric acid as a catalyst. Aftertreatment, anhydrous sodium carbonate is used to neutralize sulfuric acid. Its disadvantages are: adopting traditional neutralization and water washing process, the discharge of waste water is large and the pollution is serious

Chinese patent CN101914021 discloses a two-step method for producing butyl lactate with high content and high optical purity. In this patent, lactic acid is used as raw material to synthesize lactide, and then refined lactide and n-butanol are used as raw materials to synthesize butyl lactate. Its disadvantages are: complex process, low yield, long esterification reaction time, unfavorable for industrial production